Professor Etienne received her bachelor's degree in History with honors from Yale University, and earned her law degree from Yale Law School. Following law school, Etienne clerked for Judge Diana G. Motz on the United States Court of Appeals for the Fourth Circuit. Before joining the faculty, she practiced criminal law in state and federal courts for several years.

Her select publications include "Understanding Parity As A First principle of Sentencing" (58 Stanford L. Rev., 2006); "The Ethics of Cause Lawyering: An Empirical Examination of Criminal Defense Lawyers as Cause Lawyers" (95 J. Crim. L. & Criminology, 2005); "The Declining Utility of the Right to Counsel in Federal Court: An Empirical Study on the Role of Defense Attorney Advocacy Under the Sentencing Guidelines" (92 California Law Review, 2004); "Remorse, Responsibility, and Regulating Advocacy: Making Defendants Pay for the Sins of Their Lawyers" (78 New York University Law Review, 2003). Her article, "Addressing Gender Based Violence in an International Context," appeared in 18 Harvard Women's Law Journal 139 (1995).

In 2004, Professor Etienne was awarded a Fulbright Grant to conduct judicial training on white collar crime in Senegal. She has made presentations at Stanford law School, the University of Chicago Law School, Northwestern University Law School, Yale Law School, University of Illinois College of Law, Fordham Law School, University of Oregon Law School, Notre Dame Law School and the American Bar Foundation. Professor Etienne was a Visiting Professor at the University of Chicago Law School during the 2007-2008 academic year. She is an Executive Board member of the AALS Section on Professional Responsibility.